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Updated: Nov 11, 2025
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Expired CO2 Measurement in Intubated or Spontaneously Breathing Patients from the Emergency Department
Published on: January 29, 2011
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Ventilatory response to CO2 with Read's rebreathing method in normal infants
Yosuke Yamada1, Nobuhide Henmi1, Hisaya Hasegawa1
1Department of Neonatology, Tokyo Women's Medical University Medical Center East, Tokyo, Japan.
Pediatric Pulmonology
|March 22, 2021
Summary
The rebreathing method effectively assesses the ventilatory response to carbon dioxide (CO2) in infants. This method is safe, quick, and reliable for evaluating infant respiratory function.
Area of Science:
- Pediatric Pulmonology
- Respiratory Physiology
Background:
- Evaluating the ventilatory response to CO2 (VRCO2) is crucial for assessing respiratory control.
- Traditional methods like the steady-state and rebreathing methods exist, but rebreathing is underutilized in infants.
- The rebreathing method offers continuous assessment of ventilatory response to gradually increasing CO2 levels.
Purpose of the Study:
- To determine the feasibility of using the rebreathing method for VRCO2 assessment in normal infants.
- To establish a reliable protocol for infant VRCO2 measurement using rebreathing.
Main Methods:
- The study involved 80 healthy infants with a mean gestational age of 39.9 weeks.
- Read's rebreathing method was employed, measuring minute volume (MV) changes against end-tidal CO2 (EtCO2) in a closed circuit.
- VRCO2 was calculated as the change in MV relative to the change in EtCO2, normalized for body weight (ΔMV/ΔEtCO2 /body weight).
Main Results:
- The VRCO2 assessment was successfully performed without adverse events in infants aged 3 days.
- The examination was brief, averaging 150 seconds, with a maximum EtCO2 of 51.1 mmHg.
- The mean VRCO2 value was 34.6 (ml/min/mmHg/kg), demonstrating good reliability with an intraclass correlation coefficient of 0.79 for repeated measurements.
Conclusions:
- The rebreathing method is a feasible and effective tool for evaluating the ventilatory response to CO2 in infants.
- This method provides a rapid and reliable assessment of respiratory center function in neonates.
- Future research will focus on preterm infants and detailed evaluation of infant respiratory control using this technique.
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